Fiber Reinforced concrete (FRc) Created and presented by: Baquero, Victor Brown, Chris Thielbar, Trenton

What is fiber reinforced concrete A concrete consisting of, cement, water, fine and coarse aggregate, along with discontinuous fibers. - Fiber reinforced concrete is an alternative way to reinforce concrete other then traditional steel rebar - Made of traditional components of concrete such as cement, water, fine and coarse aggregate, with and addition of fiber reinforcement - The main purpose of fiber reinforced concrete it to improve flexural behavior

- Top left steel fiber reinforced concrete beams - Top right glass fiber reinforce concrete mix - Bottom left precast steel fiber reinforced tunnel walls - Bottom right counter top made with glass fiber reinforce concrete

Types of fibers Types of fibers include Steel Plastic Glass Polyester, Polypropylene, Polyethylene Glass Natural materials Wood cellulose, Bamboo, Elephant grass All are available is different shapes sizes and materials Pictures, STEEL, GLASS, PLASTIC(Polyester), ELEPHANT GRASS - Glass, ordinary glass fibers cannot be used in portland cement mortars because of the chemical reactions caused by the cement, therefore alkali resistance glass fibers are used. - Natural materials -bamboo- modulus of elasticity is similar to concrete, susceptible to volume changes in water, increase ultimate tensile strength -elephant grass-very durable, alkali resistance, small dimensional changes, increases flexural and impact strength - back in the olden days people used materials such are hay and hoarse hair to reinforce their concrete

Types of fibers Steel Shapes Steel fibers are adhered together before mixing and separate while mixing to ensure uniform distribution - Steel fiber come in different shapes and sizes - Depending on the application the shape of the steel fiber would be selected. - The gluing of the fibers into the bundles guarantees homogeneous distribution. A hooked end which slowly deforms during pull-outs is generally considered as the best form of anchorage

Advantages of using fiber reinforced concrete versus plain concrete Improves toughness of concrete Flexural strength is improved by up to 30% by decreasing the propagation of cracks Improves tensile strength More economical than steel reinforcement Less prone to corrosion Gives an alternative way to reinforce concrete other then traditional steel rebar - Improves toughness by allowing the cement to bond to the fibers causing more resistance to damaging loads and more resistant to impact - Plain concrete fails because it is a very brittle and has a low tolerance for deflections. With added fibers the concrete has a greater ability to withstand deflections b/c fibers resist the tensile forces. In result the concrete does not break immediately after the appearance of first crack. - Do to the resistance between fibers and concrete tensile strength is increased. Depends also on the types of fibers used to reinforce. Plastic/glass fibers will not improve that much while certain steel fibers can have a relatively decent improvement on tensile strength. May reduce slab thickness and eliminate use of conventional reinforcement

PCC FRC - We can see from the photos when we have a load causing bending on a plain concrete after the appearance of the first crack little additional load is required to rupture the concrete. With the addition of fiber reinforcement we increase ductility therefore more load can be applied before rupture. This also increases the deflection allowed in the concrete

Corrosion Unlike rebar there is not galvanic cell created in the fibers No anodic/cathodic reaction pH level of concert protects steel fibers from corrosion - Because fibers are discontinuous there is not galvanic cells created in the fibers - Corrosion, tests at the Battelle Laboratories in Columbus, Ohio, shoed minimum corrosion of steel fibers and no adverse effect after 7 years of exposure to deicing salt - For corrosion to occur you need a anodic and catholic metal. Fibers such as plastics and glass do not have these properties - All though some fibers consist of steel there are many that have not corrosive materials such as plastics, glass, and natural materials. - Ph level- creates a thin protective layer of iron oxide

Applications Applications include: Pipes Tilt-up Panels Shotcrete Slabs Counters tops Bath tubs Tiles - Any material made from concrete can be reinforced using fibers - Pipes are precast and placed at job site - Tilt-up panels can be precast or placed on sight and then lifted in place, used to build structural walls - Shotrete is use mainly in tunnels and moldings. The fibers help improve toughness - Slabs, due to the reinforcement less material can be used to achieve desired strength resulting in less cost - Counter tops, bath tube and tiles use glass fiber reinforce concrete

Properties Durability Workability Made with a high content of cement and low water to cement ratio When properly compacted and cured, concrete with steel fibers is very durable Workability Affects workability Compensate by adding superplasticizers - Just like regular concrete, FRC durability would depend on the cured time and the conditions. In addition, since FRC requires a high content of cement and low water to cement ratio, the FRC durability should improved as well. - Workability due to low water to cement ratio and addition of fibers the workably suffers, we can compensate by adding superplasticizers - Slump tests may give false indications of workability, because concrete mixtures containing fibers giving the mixture a dense consistencies; however, the placeability and compactability of concrete is much better than reflected by the dense consistency.

Properties Compressive behavior of steel FRC Tensile behavior Keeps integrity after failure Strength slightly enhanced Tensile behavior increase tensile strength Has little effect on the modulus of elasticity, drying shrinkage, and creep - Typically we expect a cone, cone and split, cone and shear, shear, and columnar type failure - Depending on type, shape, and fiber distribution even after a compressive failure more than less a FRC sample will keep its original shape - Like previously mentioned FRC will increases toughness and significantly improve flexural strength

Production Production is guided and controlled mainly by the American Concrete Institute, ASTM, and various building codes Production involves 5 Steps Determine typical Uses and Specifying FRC Materials Mixture Proportioning Batching, Mixing, Delivery and Sampling Placing and Finishing 1- The application will dictate the type of FRC that will be used ASM 2- Selection of material will depend on the type of FRC you will need e.g. Fibers steel, glass, plastic 3- General guidance can be found in ACI 211, normally do not require adjustments to mixutre. Slump is not a good indicator for workability 4- fibers need to be added uniformly to the mixture you do not want clumps in fibers - Some are designed to be added in their water soluble packaging 5- method of placing concrete that can be used for FRC are similar to thoughts uses to place Portland cement concrete such as chutes, Pumps, conveyor, tremie, shotcrete, and crane bucket - Consolidation can be done with mechanical vibration

Summary Fiber reinforced concrete is one of the oldest methods for reinforcing concrete The main purpose of fiber reinforcement is to increases its structural integrity and improve flexural behavior There are many different types of fiber that can be used for concrete reinforcement. Is an economical way to reinforced concrete compared to regular steel.

References Mamlouk, Michael, and John Zaniewski. Materials for Civil and Construction Engineers. Second Edition. N.J.: Pearson Hall, 2006. 576. Print Mehta, P.K., and P.J.M Monteiro. "Fibers in Concrete." University of Californa, Berkeley, 04,May,2006. Web. 1 Dec 2010. <http://www.ce.berkeley.edu/~paulmont/241/fibers.pdf Nemati, Kamran. "Progress in Conctet Technology: Fiber Reinforced Conctete (FRC)." University of Wahington. University of Washington, Seattle, Wahington, USA. Spring 2010. Lecture. SMiRT 19, . "WOKSHOP ON: Fiber Reinforced Concrete." ASMiRT, 17,August,2007. Web. 1 Dec 2010. <http://www.iasmirt.org/iasmirt-2/SMiRT19/SMiRT19_WH3_Tatnall.pdf>.